Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current
Assmy, Philipp . et. al.-- 6 pages, 4 figures Diatoms of the iron-replete continental margins and North Atlantic are key exporters of organic carbon. In contrast, diatoms of the iron-limited Antarctic Circumpolar Current sequester silicon, but comparatively little carbon, in the underlying deep ocea...
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ftcsic:oai:digital.csic.es:10261/96362 2024-02-11T09:58:28+01:00 Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current Assmy, Philipp Arrieta López de Uralde, Jesús M. Latasa, Mikel Scharek, Renate Wolf-Gladrow, Dieter 2013-12 http://hdl.handle.net/10261/96362 https://doi.org/10.1073/pnas.1309345110 unknown National Academy of Sciences (U.S.) https://doi.org/10.1073/pnas.1309345110 doi:10.1073/pnas.1309345110 issn: 0027-8424 e-issn: 1091-6490 Proceedings of the National Academy of Sciences 110(51): 20633-20638 (2013) http://hdl.handle.net/10261/96362 24248337 none Top-down control Evolutionary arms race Geo-engineering artículo http://purl.org/coar/resource_type/c_6501 2013 ftcsic https://doi.org/10.1073/pnas.1309345110 2024-01-16T09:58:33Z Assmy, Philipp . et. al.-- 6 pages, 4 figures Diatoms of the iron-replete continental margins and North Atlantic are key exporters of organic carbon. In contrast, diatoms of the iron-limited Antarctic Circumpolar Current sequester silicon, but comparatively little carbon, in the underlying deep ocean and sediments. Because the Southern Ocean is the major hub of oceanic nutrient distribution, selective silicon sequestration there limits diatom blooms elsewhere and consequently the biotic carbon sequestration potential of the entire ocean. We investigated this paradox in an in situ iron fertilization experiment by comparing accumulation and sinking of diatom populations inside and outside the iron-fertilized patch over 5 wk. A bloom comprising various thin- and thick-shelled diatom species developed inside the patch despite the presence of large grazer populations. After the third week, most of the thinner-shelled diatom species underwent mass mortality, formed large, mucous aggregates, and sank out en masse (carbon sinkers). In contrast, thicker-shelled species, in particular Fragilariopsis kerguelensis, persisted in the surface layers, sank mainly empty shells continuously, and reduced silicate concentrations to similar levels both inside and outside the patch (silica sinkers). These patterns imply that thick-shelled, hence grazer-protected, diatom species evolved in response to heavy copepod grazing pressure in the presence of an abundant silicate supply. The ecology of these silica-sinking species decouples silicon and carbon cycles in the iron-limited Southern Ocean, whereas carbon- sinking species, when stimulated by iron fertilization, export more carbon per silicon. Our results suggest that large-scale iron fertilization of the silicate-rich Southern Ocean will not change silicon sequestration but will add carbon to the sinking silica flux P.A. was supported through Deutsche Forschungsgemeinschaft–Cluster of Excellence “The Ocean in the Earth System” and the Centre for Ice, Climate and Ecosystems at ... Article in Journal/Newspaper Antarc* Antarctic North Atlantic Southern Ocean Digital.CSIC (Spanish National Research Council) Antarctic Southern Ocean Proceedings of the National Academy of Sciences 110 51 20633 20638 |
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Open Polar |
collection |
Digital.CSIC (Spanish National Research Council) |
op_collection_id |
ftcsic |
language |
unknown |
topic |
Top-down control Evolutionary arms race Geo-engineering |
spellingShingle |
Top-down control Evolutionary arms race Geo-engineering Assmy, Philipp Arrieta López de Uralde, Jesús M. Latasa, Mikel Scharek, Renate Wolf-Gladrow, Dieter Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current |
topic_facet |
Top-down control Evolutionary arms race Geo-engineering |
description |
Assmy, Philipp . et. al.-- 6 pages, 4 figures Diatoms of the iron-replete continental margins and North Atlantic are key exporters of organic carbon. In contrast, diatoms of the iron-limited Antarctic Circumpolar Current sequester silicon, but comparatively little carbon, in the underlying deep ocean and sediments. Because the Southern Ocean is the major hub of oceanic nutrient distribution, selective silicon sequestration there limits diatom blooms elsewhere and consequently the biotic carbon sequestration potential of the entire ocean. We investigated this paradox in an in situ iron fertilization experiment by comparing accumulation and sinking of diatom populations inside and outside the iron-fertilized patch over 5 wk. A bloom comprising various thin- and thick-shelled diatom species developed inside the patch despite the presence of large grazer populations. After the third week, most of the thinner-shelled diatom species underwent mass mortality, formed large, mucous aggregates, and sank out en masse (carbon sinkers). In contrast, thicker-shelled species, in particular Fragilariopsis kerguelensis, persisted in the surface layers, sank mainly empty shells continuously, and reduced silicate concentrations to similar levels both inside and outside the patch (silica sinkers). These patterns imply that thick-shelled, hence grazer-protected, diatom species evolved in response to heavy copepod grazing pressure in the presence of an abundant silicate supply. The ecology of these silica-sinking species decouples silicon and carbon cycles in the iron-limited Southern Ocean, whereas carbon- sinking species, when stimulated by iron fertilization, export more carbon per silicon. Our results suggest that large-scale iron fertilization of the silicate-rich Southern Ocean will not change silicon sequestration but will add carbon to the sinking silica flux P.A. was supported through Deutsche Forschungsgemeinschaft–Cluster of Excellence “The Ocean in the Earth System” and the Centre for Ice, Climate and Ecosystems at ... |
format |
Article in Journal/Newspaper |
author |
Assmy, Philipp Arrieta López de Uralde, Jesús M. Latasa, Mikel Scharek, Renate Wolf-Gladrow, Dieter |
author_facet |
Assmy, Philipp Arrieta López de Uralde, Jesús M. Latasa, Mikel Scharek, Renate Wolf-Gladrow, Dieter |
author_sort |
Assmy, Philipp |
title |
Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current |
title_short |
Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current |
title_full |
Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current |
title_fullStr |
Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current |
title_full_unstemmed |
Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current |
title_sort |
thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited antarctic circumpolar current |
publisher |
National Academy of Sciences (U.S.) |
publishDate |
2013 |
url |
http://hdl.handle.net/10261/96362 https://doi.org/10.1073/pnas.1309345110 |
geographic |
Antarctic Southern Ocean |
geographic_facet |
Antarctic Southern Ocean |
genre |
Antarc* Antarctic North Atlantic Southern Ocean |
genre_facet |
Antarc* Antarctic North Atlantic Southern Ocean |
op_relation |
https://doi.org/10.1073/pnas.1309345110 doi:10.1073/pnas.1309345110 issn: 0027-8424 e-issn: 1091-6490 Proceedings of the National Academy of Sciences 110(51): 20633-20638 (2013) http://hdl.handle.net/10261/96362 24248337 |
op_rights |
none |
op_doi |
https://doi.org/10.1073/pnas.1309345110 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
110 |
container_issue |
51 |
container_start_page |
20633 |
op_container_end_page |
20638 |
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1790594114511699968 |